Should You Leave the AC On for Your Cat or Dog?

I've been told that in the Mother Jones DC bureau last week, a debate raged over whether or not it's only crazy cat ladies who leave the air conditioner on all day for pets. I can see both sides: Sure, it's pitiful to see dogs pant and cats make themselves as flat as possible to beat the heat, especially during gnarly heat waves. And yes, it's true that pets are unable to doff their fur coats.

On the other hand, their ancestors lived outside for eons before we domesticated them, so surely they must be heartier than we give them credit for. What's more, round-the-clock AC is exorbitantly expensive and contributes significantly to climate change, as the New York Times recently reported. Because of the soaring demand for air conditioning worldwide, and because the gases emitted by modern cooling equipment are extremely potent planet warmers, scientists estimate that AC units could account for a staggering 27 percent of global warming by 2050.

So is it really necessary to chill Fido all day long? I decided to call a few veterinarians to settle the argument once and for all. Dr. Helen Myers, veterinarian at the ASPCA's Animal Poison Control Center, had this to say in an email:

When the temperature and humidity rise, it becomes crucial to keep our pets comfortable and safe. Animals cool themselves by panting, a process of exchanging warm air from their lungs for the cooler air outside. This cannot happen when it is hot and humid, which leads to increased risk for heat stress and exhaustion. Leaving the air circulating with fans or, better yet, leaving the air conditioning on will help to keep pets cool and healthy. Thermostats should ideally be set at 78-80 degrees, an appropriate comfort level for most pets. Basements are typically cooler than the rest of the house, so if your basement is a comfortable place for your pet to be, having them spend time down there during a heat wave is also an option. Pets should also always have access to fresh water, as they can get dehydrated.

Both cats and dogs are susceptible to excessive heat and humidity, but cats are more likely to control their activity so as not to add heat from muscle activity. Elderly, overweight, and pets with heart or lung diseases should be carefully watched, as they are highly susceptible to heat stroke. Pets with short muzzles like pugs, bulldogs and Persian cats are at a higher risk of becoming overheated because they cannot effectively pant. These pets should be kept in rooms with air conditioning so they can stay cool.

Kimberly May, a veterinarian and spokeswoman for the American Veterinary Medicine Association, added that it's important to observe your pet and adjust the indoor temperature according to its particular needs. "Keep an eye on your pet and see where your pet hangs out," says May. "If your dog is constantly by the AC vent, you probably shouldn't turn it off. But if you see the dog sitting in the sunlight, you might have a little more leeway." As a general rule of thumb, cats are often slightly more heat-tolerant than dogs, and for both species, the longer the fur, the more uncomfortable the animal will be in extreme heat.

As for the argument that animals don't need AC since their forebears dealt with heat just fine, May doesn't buy it. "We've domesticated them and ruined all that," she says. "It's not smart to make an assumption about their needs based on their ancestors. We've changed their diets; we've changed a lot of things."

A few other tips from May: You can try putting ice in your pet's water bowl, but only if your animal is comfortable with it; some cats and dogs are freaked by ice and won't drink ice water at all. Some dogs like the pricey cooling pads sold at pet stores and on the internet (this one is $79.99 on eBay) but others won't go near them. Walk dogs in the early morning or evening, and keep the walks short. Don't go running with your dog, since dogs will keep going, even if they're overheating.